Metal hardness measuring instrument



`umle 12, 1962 W, 1, CRlCHE 3,038,330

METAL HARDNESS MEASURING INSTRUMENT Filed July l5, 1960 /J l u r INVENTOR.

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iatented June i2, i952 3,038,330 METAL HARDNESS MEASURE-IG HNSTRUMENT William ll. Criche, Dearborn, Mich., assigner to George Q. McNamara, doing business as The Hard Cheli {Company, etroit, Mich., au assumed name company of Michigan Filed .liuly i3, 196?, Ser. No. 42,61() 6 tCiaims. (Cl. 737

This invention `relates to an accurate metal hardness measuring instrument completely devoid of release mechanism influence in testing.

Metal hardness measuring instruments have been ernployed heretofore to facilitate the testing of metals to determine their hardness, however, the several devices of the prior art have not proven entirely satisfactory inasmuch as they are complicated in design and construction, expensive to manufacture, diiiicult to use and position, and usually required that work piece be brought to the instrument, and further require careful use to avoid influencing the measurement through operation of the release mechanism.

With the foregoing in view, the primary object of the invention is to provide an accurate metal hardness measuring instrument which is simple in design and construction, inexpensive to manufacture, easy to use, easy to transport to the test piece, and which cannot transfer release mechanism iniiuence to the measurement of the hardness of the test piece.

An object of the invention is to provide a ball drop hardness testing instrument wherein the device is settable by inverting the instrument to effect lay-passing of the ball past spring fingers having detents for holding the ball in the set position.

An object of the invention is to provide spring fingers having ball holding detents and fa cam-plunger adjacent thereto adapted to radially spread the fingers and detents outwardly so as to drop the ball from the set position to the test piece without release mechanism influence on the ball drop.

An object of the invention is to provide a collar supporting the spring fingers.

An object of the invention is to provide a device which can be used by experienced as well 'as inexperienced oper-ators.

These and other objects of the invention will become apparent by reference to the following description of a metal hardness measuring instrument embodying the invention taken in connection with the accompanying drawing in which:

FIG. l is a side-elevational view of the device showing the viewing window and scale.

FlG. 2 is `an enlarged and foreshortened cross-sectional view of FIG. l, taken on the line 2-2 thereof showing the internal construction; and

FIG. 3 is a cross-sectional View of FIG. 2 taken on a line 3-3 thereof showing the ball holding spring lingers and detents.

Referring now 'to the drawing wherein like numerals refer to like or corresponding parts throughout the several views, the metal hardness measuring instrument disclosed therein to illustrate the invention comprises a ball drop cylinder it) having a bottom end lil and a top end l2 preferably made of transparent material for easy viewing therethrough surrounded by an outer protective casing i3 having a sidewall window 14 therein, a bottom socket l5 attached to the outer casing 13 by a set screw lo and having `a bottom opening 17 axially aligned with the cylinder lib. The collar 18 rests on the cylinder l@ and nests inside the casing 13 and is axially aligned with the cylinder lo and supports the spring lingers 19 above the cylinder llll and collar 13 in axial alignment with the cylinder 1t? and it is to be noted that an arcuate ridge or detent 20 is disposed on the iingers t9 extending radially inwardly so as to contact the ball 2l in supporting relationship as shown in FIG. 2.

More particularly the cap 22 surrounds the upper end of the casing lt?, cylinder i3, collar i8 and spring fingers 2li and is spaced thereabove slightly to house the cam-plunger 23 which has a neck 24 extending through the cap 22 upon which the thumb button 25 is secured and it is obvious that by depressing `the thumb-button 25 that movement is transferred to the cam-plunger 23 moving the upper ends of the spring lingers 19 outwardly so as to move the detents 2d radially outwardly `out of ball 2l supporting relationship so as to permit the ball 2l. to fall entirely without release mechanism iniiuence through the cylinder to the aperture J7 so as to impact against the test piece upon which the device sits.

The ball bounces upwardly from the test piece and the height the ball bounce is registered on the scale 26 disposed on the cylinder lil.

it will be noted that the collar 13, spring fingers i9, and ball supporting detents 2i? are preferably made of one piece of material by machining same from tubular stock and slitting same to form individual flexible spring ingers for co-operation with the cam-plunger 23.

After lthe ball has dropped in Ia test, the user inverts the device from the position seen in FIGS. l and 2 whereupon the ball drops from the point adjacent the aperture 17' and, due to the fact that the ball builds up momentum, it forces its way cam-wise past the detents 2t? and moves to the position seen in FIG. 2. Upon righting the instrument to the position seen in the drawing the ball acquires no momentum so that it cannot flex the detents 2i) and spring fingers i9 outwardly thereby resting on the detents 2d as supported by the iiexible spring `lingers i9.

In use, the device is positioned yon a test piece as seen in FIGS. l and 2 and the user then places the thumb on the button 25 and presses downwardly whereupon the camplunger `23 is moved downwardly against. the tops of the spring fingers i9 spreading them radially outwardly and moving the detents .2d therewith out of ball supporting relationship whereupon the ball 2i drops as previously stated.

The length `of the ball drop, fthe material of the ball, the hardness of the ball, and the increments lon the scale 26 are co-ordinated so that the height of the ball in its bounce reads against the scale to give an accepted reading in the industry.

It has been found that `a tungsten-carbide ball 2l proves most suitable with the device as integrated and provides a much more accurately reading and durable test instrument.

The inventive hardness measuring instrument with these features constitutes a compact, durable, neat appearing, easily oper-ated, and non-release-iniiuenced device which is easily transported to the job `and easily and accurately operable with complete simplicity.

Although but a single embodiment of the invention has been shown and described in detail, it is obvious that many changes may be made in the size, shape, detail, and arrangements of the various elements of the invention within the scope of the appended claims.

I claim:

l. A. small, compact, easily transportable, and accurate metal hardness measuring instrument which is easily settable, easily releasable, and completely devoid of -release mechanism influence in operation comprising a cylinder constituting a vertical non-interfering ball dropping chamber having `a lower end open restable on a test piece and an upper open end; said cylinder having at least one transparent `side for viewing the ball bounce height therethrough, a scale readable relative to the ball on said cylinder adjacent said transparent side, a collar at the top of said cylinder, spring lingers on -said collar extending upwardly therefrom; said `collar and lingers constituting an axial extension of said ball dropping chamber, detents on said lingers extending radially inwardly, a plunger above said lingers having a cam-portion contacting said lingers adapted to move said lingers radially outwardly to spread said detents apart so as to enlarge the diametrical space therebetween, and a ball disposed in said cylinder of a size so co-ordinated as to normally rest on said linger detents; -said ball being non-inliuencewise dropable oli said detents by manually moving said plunger camportion downwardly to spread said lingers apart to move said detents radially outwardly out of ball supporting position to eliect ball dropping.

2. A small, compact, easily transportable, and accurate metal hardness measuring instrument which is easily settable, easily releasable, and `completely devoid of release mechanism inliuence in operation comprising a cylinder constituting a vertical non-interfering ball dropping charnber having a lower open end restable on a test piece and an upper end open; said cylinder having at least one transparent side for viewing the ball bounce height therethrough, a scale readable relative to the ball on said cylinder adjacent said transparent side, at least one spring linger extending upwardly from said cylinder; said at least one linger constituting an axial extension of said ball dropping chamber, a detent on said linger extending radially inwardly, a plunger above said linger having a cam-portion contacting said linger adapted to cam said linger radially outwardly to spread said detent outwardly, land a ball disposed in said cylinder of a size so co-ordinated `as to normally rest on said linger detent; said ball being noninliuence-Wise dropable olir said detent by manually moving said plunger-cam portion downwardly to llex said finger outwardly 'to move said detent radially outwardly out of ball supporting position to drop said ball.

3. A small, compact, easily transportable and locatable metal hardness testing and indicating measuring instrument which is easily settable, and releasable entirely without influence of the release means comprising a cylinder having at least one transparent side constituting a side view window, an open top end and an open bottom end; at least 4one springable linger adjacent said cylinder top end lying in the plane of said cylinder `and disposed so as to be radially outwardly spring-wise movable, a detent on said linger intermediate the ends thereof movable with said linger so as to move radially, a ball in said cylinder adapted to spring-Wise drop past said detent to the set position by inverting said cylinder; said linger and detent being adapted to support said ball in the set position on said detent when said cylinder is normally vertically disposed on its bottom end, a canrplunger above said linger manually depressible thereaigainst to move said linger spring-wise outwardly Ito move said detent radially out of ball supporting position to drop said ball Without release inliuence downwardly in said cylinder to impact against the test piece upon which said cylinder bottom rests t0 elect ball upward bouncing, `and a scale on said cylinder readable through `said Window against said ball to determine the ball bounce height thereon; said scale being calibrated with said ball drop length, ball material, and ball hardness for measuring the hardness of the test piece relative to theheight of the ball bounce from a test piece.

4. In a device as set forth in claim 3 a collar adjacent said cylinder ltop supporting said spring linger.

5. A small, compact, easily transportable and locatable metal hardness measuring instiument which is easily settable and which is releasable entirely without influence of the release means comprising a cylinder having at least one side window, an open top end and an open bottom end; springable lingers Vadjacent said cylinder top end lying in the plane of said cylinder and disposed so las to be radially spring-wise movable, a detent on each said finger intermediate the ends thereof movable with said linger so as to move radially, `a ball in said cylinder adapted to springwise drop past said detent to the set position by inverting said cylinder; said linger and detent being adapted to support said ball in the set position on said detent when said cylinder is normally vertically disposed on its bottom end, a cam-plunger above said lingers manually depressible thereagainst to move said linger springwise outwardly to move said detent radially out of ballsupporting position to drop said ball without release influence downwardly in said cylinder to impact against the test piece upon which said cylinder bottom rests to effect ball upward bouncing, and a scale on said cylinder readable through said window against said ball to determine the ball bounce height thereon; `said scale being calibrated with said ball drop length, ball material, and ball hardness for measuring the hardness of the test piece relative to the height of the ball bounce on a test piece.

6. In device as set forth in claim 5 a collar adjacent said cylinder top supporting said spring lingers.

Lipps Apr. 15, 1924 Han May 25, 1926 

